Multimedia and group communications have become an important aspect of telecommunications, and the demand for such continues to increase. For instance, the Final Report of the Public Safety Wireless Advisory Committee to the Federal Communications Committee (“FCC”), dated 1996, expressed the critical need for communication resources for multimedia. Subsequently in 1998, the FCC established a band plan for the 764 MHz frequencies that included spectrum set aside for public safety wideband. In addition, the Internet Engineering Task Force (“IETF”) has developed a suite of protocols that are designed for use in multimedia communications. These protocols include a Session Initiation Protocol (“SIP”), for instance as described in the IETF Request for Comment (“RFC”) 3261, a Session Announcement Protocol (“SAP”), for instance as described in RFC 2974, and a Session Description Protocol (“SDP”), for instance as described in RFC 2327.
Since its approval in early 1999 as an official standard, SIP has gained tremendous market acceptance for signaling communications services on the Internet. As such, numerous products incorporate the SIP standard, including but not limited to SIP desktop telephones, SIP telephony servers, and personal computing (“PC”) devices running SIP applications. SIP is a text-based signaling transactional protocol, similar to Hypertext Transfer Protocol (“HTTP”) and Simple Mail Transfer Protocol (“SMTP”), and works in the Application layer of the Open Systems Interconnection (“OSI”) communications model. A SIP message is used for call control, e.g., to control interactive communications sessions or calls, such as voice, video, and chat, between users (also referred to herein as callers) in a communications network. Each user is typically associated with a communications device (also referred to herein as a terminal device) that is connected to the network.
SIP was designed for controlling media sessions and for establishing media sessions between an initiating endpoint and one recipient endpoint or a group of recipient endpoints. Moreover, for communications between a group of endpoints, there are typically limited shared resources for transmitting and receiving media. Therefore, communication systems may accordingly implement some form of floor control to control access to those limited resources at any given time. It is known to use separate protocols for call control and floor control. However, a problem with this approach is that it requires two separate message exchanges during call set-up (i.e., one for the session and one for the floor) in order to start communications. This can cause an undesired delay in call set-up as both message exchanges need to complete in order to begin transmitting and receiving media.
Thus, what is needed is a method and apparatus to describe a floor control profile that corresponds to a given session that may be dynamically assigned for each session, and to associate floor control parameters with a specific session and media stream(s) at call initiation to minimize call set-up times. It is further desirable that at call set-up communication resources are only reserved for callers that will be sourcing media during a session.